[PATCH 2/3] hw/sensor: max31785 : add fan status, tach target, and tach input object properties

Maheswara Kurapati posted 3 patches 3 years, 7 months ago
Maintainers: Paolo Bonzini <pbonzini@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Eduardo Habkost <eduardo@habkost.net>
[PATCH 2/3] hw/sensor: max31785 : add fan status, tach target, and tach input object properties
Posted by Maheswara Kurapati 3 years, 7 months ago
This fix adds object properties for the FAN_COMMAND_1 (3Bh), STATUS_FANS_1_2 (81h),
READ_FAN_SPEED_1 (90h) registers for the MAX31785 instrumentation. An additional
property tach_margin_percent updates the tachs for a configured percent of
FAN_COMMAND_1 value.

Register                property
--------------------------------------
FAN_COMMAND_1 (3Bh)     fan_target
STATUS_FANS_1_2 (81h)   status_fans_1_2
READ_FAN_SPEED_1 (90h)  fan_input

Signed-off-by: Maheswara Kurapati <quic_mkurapat@quicinc.com>
---
 hw/sensor/max31785.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/hw/sensor/max31785.c b/hw/sensor/max31785.c
index 8b95e32481..1cb31c2e82 100644
--- a/hw/sensor/max31785.c
+++ b/hw/sensor/max31785.c
@@ -164,6 +164,7 @@ typedef struct MAX31785State {
     uint64_t mfr_date;
     uint64_t mfr_serial;
     uint16_t mfr_revision;
+    int8_t  tach_margin_percent[MAX31785_FAN_PAGES];
 } MAX31785State;
 
 static uint8_t max31785_read_byte(PMBusDevice *pmdev)
@@ -530,6 +531,27 @@ static void max31785_init(Object *obj)
 
     for (int i = MAX31785_MIN_FAN_PAGE; i <= MAX31785_MAX_FAN_PAGE; i++) {
         pmbus_page_config(pmdev, i, PB_HAS_VOUT_MODE);
+
+        /* STATUS_FANS_1_2 (81h) for FAULT and WARN bits */
+        object_property_add_uint8_ptr(obj, "status_fans_1_2[*]",
+                            &pmdev->pages[i].status_fans_1_2,
+                            OBJ_PROP_FLAG_READWRITE);
+
+        /* FAN_COMMAND_1 (3Bh)  target fan speed (pwm/rpm) */
+        object_property_add_uint16_ptr(obj, "fan_target[*]",
+                            &pmdev->pages[i].fan_command_1,
+                            OBJ_PROP_FLAG_READWRITE);
+
+        /* margin fan speed in percent (could be +ve or -ve) */
+        object_property_add_int8_ptr(obj, "tach_margin_percent[*]",
+                            &(MAX31785(obj))->tach_margin_percent[i],
+                            OBJ_PROP_FLAG_READWRITE);
+
+        /* READ_FAN_SPEED_1 (90h) returns the fan speed in RPM */
+        object_property_add_uint16_ptr(obj, "fan_input[*]",
+                            &pmdev->pages[i].read_fan_speed_1,
+                            OBJ_PROP_FLAG_READWRITE);
+
     }
 
     for (int i = MAX31785_MIN_TEMP_PAGE; i <= MAX31785_MAX_TEMP_PAGE; i++) {
-- 
2.25.1
Re: [PATCH 2/3] hw/sensor: max31785 : add fan status, tach target, and tach input object properties
Posted by Peter Maydell 3 years, 7 months ago
On Thu, 14 Jul 2022 at 14:04, Maheswara Kurapati
<quic_mkurapat@quicinc.com> wrote:
>
> This fix adds object properties for the FAN_COMMAND_1 (3Bh), STATUS_FANS_1_2 (81h),
> READ_FAN_SPEED_1 (90h) registers for the MAX31785 instrumentation. An additional
> property tach_margin_percent updates the tachs for a configured percent of
> FAN_COMMAND_1 value.
>
> Register                property
> --------------------------------------
> FAN_COMMAND_1 (3Bh)     fan_target
> STATUS_FANS_1_2 (81h)   status_fans_1_2
> READ_FAN_SPEED_1 (90h)  fan_input

This commit message is missing the rationale -- why do we need this?

I am also not sure that we should be defining properties that are
just straight 1:1 with the device registers. Compare the way we
handle temperature-sensor values, where the property values are
defined in a generic manner (same units representation) regardless
of the underlying device and the device's property-set-get implementation
then handles converting that to and from whatever internal implementation
representation the device happens to use.

thanks
-- PMM
Re: [PATCH 2/3] hw/sensor: max31785 : add fan status, tach target, and tach input object properties
Posted by Maheswara Kurapati 3 years, 7 months ago
Hello Peter,

Thank you for the review.  Please see my comments inline.

Thank you,

Mahesh

On 7/14/22 8:10 AM, Peter Maydell wrote:
> On Thu, 14 Jul 2022 at 14:04, Maheswara Kurapati
> <quic_mkurapat@quicinc.com> wrote:
>> This fix adds object properties for the FAN_COMMAND_1 (3Bh), STATUS_FANS_1_2 (81h),
>> READ_FAN_SPEED_1 (90h) registers for the MAX31785 instrumentation. An additional
>> property tach_margin_percent updates the tachs for a configured percent of
>> FAN_COMMAND_1 value.
>>
>> Register                property
>> --------------------------------------
>> FAN_COMMAND_1 (3Bh)     fan_target
>> STATUS_FANS_1_2 (81h)   status_fans_1_2
>> READ_FAN_SPEED_1 (90h)  fan_input
> This commit message is missing the rationale -- why do we need this?
The STATUS_FANS_1_2, and READ_FAN_SPEED_1 registers are read-only. I 
added these properties to simulate the error device faults.
>
> I am also not sure that we should be defining properties that are
> just straight 1:1 with the device registers. Compare the way we
> handle temperature-sensor values, where the property values are
> defined in a generic manner (same units representation) regardless
> of the underlying device and the device's property-set-get implementation
> then handles converting that to and from whatever internal implementation
> representation the device happens to use.
I am not sure I understood your comment.  I checked hw/sensors/tmp105.c, 
in which a "temperature" property is added for the tmp_input field in 
almost the similar way what I did, except that the registers in the 
MAX31785 are in direct format.
>
> thanks
> -- PMM

Re: [PATCH 2/3] hw/sensor: max31785 : add fan status, tach target, and tach input object properties
Posted by Peter Maydell 3 years, 7 months ago
On Thu, 14 Jul 2022 at 22:14, Maheswara Kurapati
<quic_mkurapat@quicinc.com> wrote:
> On 7/14/22 8:10 AM, Peter Maydell wrote:
> > On Thu, 14 Jul 2022 at 14:04, Maheswara Kurapati
> > <quic_mkurapat@quicinc.com> wrote:
> >> This fix adds object properties for the FAN_COMMAND_1 (3Bh), STATUS_FANS_1_2 (81h),
> >> READ_FAN_SPEED_1 (90h) registers for the MAX31785 instrumentation. An additional
> >> property tach_margin_percent updates the tachs for a configured percent of
> >> FAN_COMMAND_1 value.
> >>
> >> Register                property
> >> --------------------------------------
> >> FAN_COMMAND_1 (3Bh)     fan_target
> >> STATUS_FANS_1_2 (81h)   status_fans_1_2
> >> READ_FAN_SPEED_1 (90h)  fan_input
> > This commit message is missing the rationale -- why do we need this?
> The STATUS_FANS_1_2, and READ_FAN_SPEED_1 registers are read-only. I
> added these properties to simulate the error device faults.

I'm not entirely sure what you have in mind here, but
QEMU doesn't generally simulate device error injection.

> > I am also not sure that we should be defining properties that are
> > just straight 1:1 with the device registers. Compare the way we
> > handle temperature-sensor values, where the property values are
> > defined in a generic manner (same units representation) regardless
> > of the underlying device and the device's property-set-get implementation
> > then handles converting that to and from whatever internal implementation
> > representation the device happens to use.

> I am not sure I understood your comment.  I checked hw/sensors/tmp105.c,
> in which a "temperature" property is added for the tmp_input field in
> almost the similar way what I did, except that the registers in the
> MAX31785 are in direct format.

Yes, that is my point. My impression is that you've provided
properties that directly match the register format of this
device because that's easy. I think that instead we should
consider what the properties are intended to do, and perhaps
have a standard convention for what format to use for particular
kinds of data, as we do for temperature already.

-- PMM